Method for configuring a telecommunication system

ABSTRACT

A method and system for configuring a CDMA telecommunications system having at least one sending entity and at least one receiving entity, each entity configured to transmit data on at least one physical channel (DPDCH) via a transport channel composite (CCTrCH) of multiple transport channels. At least one entity includes a data processing module configured to determine for each transport channel a first parameter (RMi) proportional to a rate matching ratio (RFi) and a second parameter representing a maximum physical rate (Ndata) and to transform for each of the transport channels a number of symbols before rate matching (Nk) into a number of symbols after rate matching (Nk+ΔNk), where the number of symbols after rate matching (Nk+ΔNk) is obtained approximately by multiplying the number of symbols before rate matching (Nk) by the rate matching ratio (RFi).

FIELD OF INVENTION

This invention relates to a method for configuring a telecommunicationsystem comprising at least one sending entity and at least one receivingentity, said sending and receiving entities implementing a step fortransmission of data transported on at least one physical channel, saidat least one physical channel transmitting a transport channel compositeunder formation and having its own maximum physical rate, said transportchannel composite comprising at least two transport channels, said datatransmission step being preceded by a data processing procedure for eachof said transport channels, said data processing procedure comprising atleast one rate matching step, said rate matching step transforming anumber of symbols before rate matching into a number of symbols afterrate matching, said number of symbols after rate matching being obtainedapproximately by multiplying said number of symbols before rate matchingby a rate matching ratio specific to each of said at least two transportchannels, said transport channel composite having a number of symbolsapproximately equal to the algebraic sum of the numbers of symbols inthe transport channels after the rate matching steps in said processingprocedures for a period common to said processing procedures.

The 3GPP (3^(rd) Generation Partnership Project) Committee is anorganization whose members originate from various regionalstandardization organizations and particularly the ETSI (EuropeanTelecommunication Standardization Institute) for Europe and the ARIB(Association of Radio Industries and Businesses) for Japan, and thepurpose of which is to standardize a 3^(rd) generation telecommunicationsystem for mobiles. The CDMA (Code Division Multiple Access) technologyhas been selected for these systems. One of the fundamental aspectsdistinguishing 3^(rd) generation systems from 2^(nd) generation systems,apart from the fact that they make more efficient use of the radiospectrum, is that they provide very flexible services. 2^(nd) generationsystems offer an optimized radio interface only for some services, forexample the GSM (Global System for Mobiles) system is optimized forvoice transmission (telephony service). 3^(rd) generation systems have aradio interface adapted to all types of services and servicecombinations.

Therefore, one of the benefits of 3^(rd) generation mobile radio systemsis that they can efficiently multiplex services that do not have thesame requirements in terms of Quality of Service (QoS), on the radiointerface. In particular, these quality of service differences implythat the channel encoding and channel interleaving should be differentfor each of the corresponding transport channels used, and that the biterror rates (BER) are different for each transport channel. The biterror rate for a given channel encoding is sufficiently small when theEb/I ratio, which depends on the coding, is sufficiently high for allcoded bits. Eb/I is the ratio between the average energy of each codedbit (Eb) and the average energy of the interference (I), and depends onthe encoding. The term symbol is used to denote an information elementthat can be equal to a finite number of values within an alphabet, forexample a symbol may be equivalent to a bit when it can only be one oftwo values.

The result is that since the various services do not have the samequality of service, they do not have the same requirement in terms ofthe Eb/I ratio. But yet, in a CDMA type system, the capacity of thesystem is limited by the level of interference. Thus, an increase in theenergy of bits coded for a user (Eb) contributes to increasinginterference (I) for other users. Therefore, the Eb/I ratio has to befixed as accurately as possible for each service in order to limitinterference produced by this service. An operation to balance the Eb/Iratio between the different services is then necessary. If thisoperation is not carried out, the Eb/I ratio would be fixed by theservice with the highest requirement, and the result will be that thequality of the other services would be “too good”, which would have adirect impact on the system capacity in terms of the number of users.This causes a problem, since rate matching ratios are definedidentically at both ends of the radio link.

This invention relates to a method for configuring a telecommunicationsystem to define rate matching ratios identically at both ends of a CDMAtype radio link.

In the ISO's (International Standardization Organization) OSI (OpenSystem Interconnection) model, a telecommunication equipment is modeledby a layered model comprising a stack of protocols in which each layeris a protocol that provides a service to the higher level layer. The3GPP committee calls the service provided by the level 1 layer to thelevel 2 layer “transport channels”. A transport channel (TrCH for short)enables the higher level layer to transmit data with a given quality ofservice. The quality of service is characterized in particular by aprocessing delay, a bit error rate and an error rate per block. Atransport channel may be understood as a data flow at the interfacebetween the level 1 layer and the level 2 layer in the sametelecommunication equipment. A transport channel may also be understoodas a data flow between the two level 2 layers in a mobile station and ina telecommunication network entity connected to each other through aradio link. Thus, the level 1 layer uses suitable channel encoding andchannel interleaving, in order to satisfy the quality of servicerequirement.

Solutions proposed by the 3GPP committee to achieve this balancing areillustrated in FIGS. 1 and 2. FIG. 1 is a diagrammatic view illustratingmultiplexing of transport channels on the downlink according to thecurrent proposal of the 3GPP committee. In the current proposal of thiscommittee, the symbols processed until the last step 130 described beloware bits.

With reference to FIG. 1, a higher level layer 101 periodically suppliestransport block sets to the level 1 layer. These sets are supplied intransport channels reference 100. A periodic time interval with whichthe transport block set is supplied to the transport channel is calledthe Transmission Time Interval (TTI) of the transport channel. Eachtransport channel has its own TTI time interval which may be equal to10, 20, 40 or 80 ms. FIG. 2 shows examples of transport channels A, B, Cand D. In this figure, the transport block set received by eachtransport channel is represented by a bar in the histogram. The lengthof the bar in the histogram represents a TTI interval of the associatedtransport channel and its area corresponds to the useful load in thetransport block set. With reference to FIG. 2, the duration of the TTIintervals associated with transport channels A, B, C and D is equal to80 ms, 40 ms, 20 ms and 10 ms respectively. Furthermore, the dottedhorizontal lines in the histogram bars indicate the number of transportblocks in each transport block set. In FIG. 2, transport channel Areceives a first transport block set A₀ comprising three transportblocks during a first transmission time interval, and a second transportblock set A₁ comprising a single transport block during the next TTIinterval. Similarly, transport channel B receives transport block setsB₀, B₁, B₂ and B₃ during four consecutive TTI intervals, comprising 0,2, 1 and 3 transport blocks respectively. Transport channel C receivestransport block sets C₀ to C₇ during eight successive TTI intervals andfinally transport channel D receives transport block sets D₀ to D₁₅during sixteen TTI intervals.

Note that a TTI interval for a given transport channel cannot overlaptwo TTI intervals in another transport channel. This is possible becauseTTI intervals increase geometrically (10 ms, 20 ms, 40 ms and 80 ms).Note also that two transport channels with the same quality of servicenecessarily have the same TTI intervals. Furthermore, the term“transport format” is used to describe the information representing thenumber of transport blocks contained in the transport block set receivedby a transport channel and the size of each transport block. For a giventransport channel, there is a finite set of possible transport formats,one of which is selected at each TTI interval as a function of the needsof higher level layers. In the case of a constant rate transportchannel, this set only includes a single element. On the other hand, inthe case of a variable rate transport channel, this set comprisesseveral elements and therefore the transport format can vary from oneTTI interval to the other when the rate itself varies. In the exampleshown in FIG. 2, transport channel A has a first transport format forthe set A₀ received during radio frames 0 to 7, and a second transportformat for set A₁ during radio frames 8 to 15.

According to the assumptions currently made by the 3GPP committee, thereare two types of transport channels, namely real time transport channelsand non-real time transport channels. No automatic repeat request (ARQ)is used in the case of an error with real time transport channels. Thetransport block set contains at most one transport block and there is alimited number of possible sizes of this transport block. Theexpressions “block size” and “number of symbols per block” will be usedindifferently in the rest of this description.

For example, the transport formats defined in the following table may beobtained:

Transport Number Corresponding format index of transport blockstransport block size 0 0 — 1 1 100 2 1 120

In this table, the minimum rate is zero bit per TTI interval. This rateis obtained for transport format 0. The maximum rate is 120 bits per TTIinterval and it is obtained for transport format 2.

Automatic repetition can be used in the case of an error with non-realtime transport channels. The transport block set contains a variablenumber of transport blocks of the same size. For example, the transportformats defined in the following table may be obtained:

Transport Number format index of transport blocks Transport block size 01 160 1 2 160 2 3 160

In this table, the minimum rate is 160 bits per TTI interval. This lateis obtained for transport format 0. The maximum rate is 480 bits per TTIinterval and is obtained for transport format 2.

Thus, considering the example shown in FIG. 2, the following descriptionis applicable for transport channels A, B, C and D:

Transport channel A TTI interval 80 ms Transport formats TransportNumber format index of transport blocks Transport block size 0 1 160 1 2160 2 3 160

In FIG. 2, the transport block set A₀ is in transport format 2, whereasA₁ is in transport format 0.

Transport channel B TTI interval 40 ms Transport formats TransportNumber format index of transport blocks Transport block size 0 0 — 1 280 2 1 80 3 3 80

In FIG. 2, transport block sets B₀, B₁, B₂ and B₃ are in transportformats 0, 1, 2 and 3 respectively.

Transport channel C TTI interval 20 ms Transport formats TransportNumber format index of transport blocks Transport block size 0 0 — 1 1100 2 1 120

In FIG. 2, transport block sets C₀, C₁, C₂, C₃, C₄, C₅, C₆ and C₇ are intransport formats 2, 2, 1, 2, 2, 0, 0 and 2 respectively.

Transport channel D TTI interval 10 ms Transport formats TransportNumber format index of transport blocks Transport block size 0 0 — 1 120 2 2 20 3 3 20

In FIG. 2, transport block sets D₀ to D₁₅ are in transport formats 1, 2,2, 3, 1, 0, 1, 1, 1, 2, 2, 0, 0, 1, 1 and 1 respectively.

For each radio frame, a transport format combination (TFC) can then beformed starting from the current transport formats for each transportchannel. With reference to FIG. 2, the transport format combination forframe 0 is ((A,2), (B,0), (C,2), (D,1)). It indicates that transportformats for transport channels A, B, C and D for frame 0 are 2, 0, 2,and 1 respectively. Index 5 is associated with this transport formatcombination in the following table that illustrates a possible set oftransport format combinations to describe the example in FIG. 2:

Transport format for Combination transport Channels Frame number withindex A B C D this combination  0 0 2 0 0 11   1 0 2 0 2 10   2 0 3 0 012   3 0 3 0 1 13   4 0 2 2 1 8  5 2 0 2 1 0  6 0 2 2 2 9  7 2 1 1 0 5 8 2 0 2 2 1 and 2  9 0 3 2 1 14 and 15 10 2 1 1 1 4 11 2 0 2 3 3 12 2 12 1 6 and 7

Therefore, with reference once again to FIG. 1, each transport channelreference 100 receives a transport block set at each associated TTIinterval originating from a higher level layer 101. Transport channelswith the same quality of service are processed by the same processingsystem 102A, 102B. A frame checking sequence (FCS) is assigned to eachof these blocks during a step 104. These sequences are used in receptionto detect whether or not the received transport block is correct. Thenext step, reference 106, consists of multiplexing the various transportchannels with the same quality of service (QoS) with each other. Sincethese transport channels have the same quality of service, they can becoded in the same way. Typically, this multiplexing operation consistsof an operation in which transport block sets are concatenated. The nextstep consists of carrying out a channel encoding operation, 108, onmultiplexed sets of blocks. The result at the end of this step is a setof coded transport blocks. A coded block may correspond to severaltransport blocks. In the same way as a sequence of transport block setsforms a transport channel, a sequence of sets of coded transport blocksis. called a coded transport channel. Channels coded in this way arethen rate matched in a step 118 and are then interleaved on theirassociated TTI intervals in a step 120 and are then segmented in a step122. During the segmentation step 122, the coded transport block setsare segmented such that there is one data segment for each multiplexingframe in a TTI interval in the channel concerned. A multiplexing frameis the smallest time interval for which a demultiplexing operation canbe operated in reception. In our case, a multiplexing frame correspondsto a radio frame and lasts for 10 ms.

As already mentioned, the purpose of the rate matching step (118) is tobalance the Eb/I ratio on reception between transport channels withdifferent qualities of service. The bit error rate BER on receptiondepends on this ratio. In a system using the CDMA multiple accesstechnology, the quality of service that can be obtained is greater whenthis ratio is greater. Therefore, it is understandable that transportchannels with different qualities of service do not have the same needsin terms of the Eb/I ratio, and that if the rate is not matched, thequality of some transport channels would be “too” good since it is fixedby the most demanding channel and would unnecessarily cause interferenceon adjacent transport channels. Therefore, matching the rate alsobalances the Eb/I ratio. The rate is matched such that N input symbolsgive N+ΔN output symbols, which multiplies the Eb/I ratio by the$\frac{N + {\Delta \quad N}}{N}$

ratio. This $\frac{N + {\Delta \quad N}}{N}$

ratio is equal to the rate matching ratio RF, except for rounding.

In the downlink, the peak/average ratio of the radio frequency power isnot very good, since the network transmits to several users at the sametime. Signals sent to these users are combined constructively ordestructively, thus inducing large variations in the radio frequencypower emitted by the network, and therefore a bad peak/average ratio.Therefore, for the downlink it was decided that the Eb/I ratio will bebalanced between the various transport channels by rate matching using asemi-static rate matching ratio${{R\quad F} \approx \frac{N + {\Delta \quad N}}{N}},$

and that multiplexing frames would be padded by dummy symbols, in otherwords non-transmitted symbols (discontinuous transmission). Dummysymbols are also denoted by the abbreviation DTX (DiscontinuousTransmission). Semi-static means that this RF ratio can only be modifiedby a specific transaction implemented by a protocol from a higher levellayer. The number of DTX symbols to be inserted is chosen such that themultiplexing frame padded with DTX symbols completely fills in theDedicated Physical Data Channel(s) (DPDCH).

This discontinuous transmission degrades the peak/average ratio of theradio frequency power, but this degradation is tolerable considering thesimplified construction of the receiving mobile station obtained with asemi-static rate matching ratio.

Referring once again to FIG. 1, the transport channels with differentqualities of service after encoding, segmentation, interleaving and ratematching are multiplexed to each other in a step 124 in order to preparemultiplexing frames forming a transport channel composite. Thismultiplexing is done for each multiplexing frame individually. Since therate of the multiplexed transport channels may be variable, thecomposite rate obtained at the end of this step is also variable. Thecapacity of a physical channel referred to as a DPDCH (DedicatedPhysical Data Channel) is limited, consequently it is possible that thenumber of physical channels necessary to transport this composite may begreater than one. When the required number of physical channels isgreater than one, a segmentation step 126 for this composite isincluded. For example, in the case of two physical channels, thissegmentation step 126 may consist of alternately sending one symbol tothe first of the two physical channels denoted DPDCH#L, and a symbol tothe second physical channel denoted DPDCH#2.

The data segments obtained are then interleaved in a step 128 and arethen transmitted on the physical channel in a step 130. This final step130 consists of modulating the symbols transmitted by spectrumspreading.

DTX symbols are dynamically inserted either for each TTI intervalseparately in a step 116, or for each multiplexing frame separately in astep 132. The rate matching ratios RF_(i) associated with each transportchannel i are determined such as to minimize the number of DTX symbolsto be inserted when the total transport channel composite rate after themultiplexing step 124 is maximum. The purpose of this technique is tolimit degradation of the peak/average ratio of the radio frequency powerin the worst case.

The rate is matched by puncturing (RF_(i)<1, ΔN<0) or by repetition(RF_(i)>1, ΔN>0). Puncturing consists of deleting −ΔN symbols, which istolerable since they are channel encoded symbols, and therefore despitethis operation, when the rate matching ratio RF_(i) is not too low,channel decoding in reception (which is the inverse operation of channelencoding) can reproduce data transported by the transport channelswithout any error (typically when RF_(i)≧0.8, in other words when notmore than 20% of symbols are punctured).

DTX symbols are inserted during one of the two mutually exclusivetechniques. They are inserted either in step 116 using the “fixedservice positions” technique, or in step 132 using the “flexible servicepositions” technique. Fixed service positions are used since they enableto carry out a blind rate detection with acceptable complexity. Flexibleservice positions are used when there is no blind rate detection. Notethat the DTX symbols insertion step 116 is optional.

During step 116 (fixed service positions), the number of DTX symbolsinserted is sufficient so that the data flow rate after this step 116 isconstant regardless of the transport format of the transport channelsbefore this step 116. In this way, the transport format of the transportchannels may be detected blind with reduced complexity, in other wordswithout transmitting an explicit indication of the current transportformat combination on an associated dedicated physical control channel(DPCCH). Blind detection consists of testing all transport formats untilthe right encoding format is detected, particularly using the framechecking sequence FCS.

If the rate is detected using an explicit indication, the DTX symbolsare preferably inserted in step 132 (flexible service positions). Thismakes it possible to insert a smaller number of DTX symbols when therates on two composite transport channels are not independent, andparticularly in the case in which they are complementary since the twotransport channels are then never at their maximum rate simultaneously.

At the present time, the only algorithms that are being defined are themultiplexing, channel encoding, interleaving and rate matchingalgorithms. A rule needs to be defined to fix a relation in the downlinkbetween the number N of symbols before rate matching and the variationΔN corresponding to the difference between the number of symbols beforerate matching and the number of symbols after rate matching.

Consider the example shown in FIG. 2. Transport channel B accepts fourtransport formats indexed from 0 to 3. Assume that the coded transportchannel originating from transport channel B produces not more than onecoded block for each transport format, as shown in the following table.

Transport channel B TTI interval 40 ms Transport formats TransportNumber of Coded format transport Transport Number of block index blocksblock size coded blocks size (N) 0 0 — 0 — 1 2 80 1 368 2 1 80 1 192 3 380 1 544

Assume that RF_(B)=1.3333 is the rate matching ratio, then the variationΔN generated by rate matching varies with each transport format, forexample as in the following table:

Transport channel B TTI interval 40 ms Transport formats TransportNumber of Coded block Variation format index coded blocks size (N) (ΔN)0 0 — — 1 1 368 123 2 1 192  64 3 1 544 181

Thus, the existence of this type of rule to calculate the variation ΔNas a function of the number N of symbols before rate matching couldsimplify negotiation of the connection. Thus, according to the examplein the above table, instead of providing three possible variations ΔN,it would be sufficient to supply a restricted number of parameters tothe other end of the link that could be used to calculate them. Anadditional advantage is that the quantity of information to be suppliedwhen adding, releasing or modifying the rate matching of a transportchannel, is very small since parameters related to other transportchannels remain unchanged.

A calculation rule was already proposed during meeting No. 6 of the worksub-group WG1 of sub-group 3GPP/TSG/RAN of the 3GPP committee in July1999 in Espoo (Finland). This rule is described in section 4.2.6.2 ofthe proposed text presented in document 3GPP/TSG/RAN/WG1/TSGR1#6(99)997“Text Proposal for rate matching signaling”. However, it introduces anumber of problems as we will demonstrate. Note the notation used inthis presentation is not exactly the same as the notation in documentTSGR1#6(99)997 mentioned above.

In order to clarify the presentation, we will start by describing thenotation used in the rest of the description.

Let i denote the index representing the successive values 1, 2, . . . ,T of the coded transport channels, then the set of indexes of thetransport formats of the coded transport channel i are denoted TFS(i),for all values of iε{1, . . . , T}. If j is the index of a transportformat of a coded transport channel i, in other words jεTFS(i), the setof indexes of coded blocks originating from the coded transport channeli for transport format j is denoted CBS(i,j) . Each coded block index isassigned uniquely to a coded block, for all transport formats and allcoded transport channels. In summary we have: $\begin{matrix}\left\{ {\left. {{\begin{matrix}{\forall{i \in \left\{ {1,\ldots \quad,T} \right\}}} \\{\forall{j \in {{TFS}(i)}}} \\{\forall{i^{\prime} \in \left\{ {1,\ldots \quad,T} \right\}}} \\{\forall{j^{\prime} \in {{TFS}\left( i^{\prime} \right)}}}\end{matrix}\left( {i,j} \right)} \neq \left( {i^{\prime},j^{\prime}} \right)}\Rightarrow{{{CBS}\left( {i,j} \right)}\bigcap{{CBS}\left( {i^{\prime},j^{\prime}} \right)}} \right. = \varnothing} \right. & (1)\end{matrix}$

where Ø is an empty set. Note that for the purposes of thispresentation, the index of a coded block does not depend on the datacontained in this block, but it identifies the coded transport channelthat produced this coded block, the transport format of this channel,and the block itself if this transport channel produces several codedblocks for this transport format. This block index is also called thecoded block type. Typically, coded transport channel i does not producemore than 1 coded block for a given transport format i, and thereforeCBS (i,j) is either an empty set or a singleton. If a coded transportchannel i produces n coded blocks for transport format j, then CBS(i,j)comprises n elements.

We will also use TFCS to denote the set of transport formatcombinations. Each element in this set may be bi-univocally representedby a list of (i,j) pairs associating each coded transport channelindexed i in {1, . . . , T} with a transport format with index j in thiscoded transport channel (jεTFS(i)). In other words, a transport formatcombination can determine a transport format j corresponding to eachcoded transport channel i. In the rest of this presentation, it isassumed that the set TFCS comprises C elements, the transport formatcombinations for this set then being indexed from 1 to C. If l is theindex of a transport format combination, then the transport format indexcorresponding to the coded transport channel indexed i in the transportformat combination with index l will be denoted TF_(i)(l). In otherwords, the transport format combination with index l is represented bythe following list:

((1,TF ₁(l)), (2,TF ₂(l)), . . . , (T,TF _(T)(l)))

The set of block size indexes for any transport format combination l isdenoted MSB(l). Therefore, we have: $\begin{matrix}{{\forall{l \in {\left\{ {1,\ldots \quad,C} \right\} {{MSB}(l)}}}} = {\bigcup\limits_{1 \leq l \leq T}{{CBS}\left( {i,{{TF}_{i}(l)}} \right)}}} & (2)\end{matrix}$

Furthermore, the number of multiplexing frames in each transmission timeinterval on the coded transport channel i is denoted F_(i). Thus, in thesending system shown in FIG. 1, any block originating from the codedtransport channel i is segmented into F_(i) blocks or segments. Based onthe current assumptions made by the 3GPP committee, the sizes of theseblocks are approximately equal. For example, if F_(i)=4 and the block onwhich segmentation step 122 is applied comprises 100 symbols, then thesegments obtained at the end of this step 122 comprise 25 symbols. Onthe other hand, if the segmented block comprises only 99 symbols, since99 is not a multiple of 4, then after segmentation there will be either3 blocks of 25 symbols with 1 block of 24 symbols, or 4 blocks of 25symbols with a padding symbol being added during the segmentation step122. However, if X is the number of symbols in the block beforesegmentation step 122, it can be written that$\left\lceil \frac{X}{F_{i}} \right\rceil$

is the maximum number of symbols per segment, the notation ┌x┐ denotingthe smallest integer greater than or equal to x.

Finally, for a coded block with type or index k, the number of symbolsin this coded block before rate matching is denoted N_(k), and thevariation between the number of symbols after rate matching and thenumber of symbols before rate matching is denoted ΔN_(k). Furthermore,note that in the rest of this text, the expressions “rate” and “numberof symbols per multiplexing frame” are used indifferently. For amultiplexing frame with a given duration, the number of symbolsexpresses a rate as a number of symbols per multiplexing frame interval.

Now that the notation has been defined, we can describe the calculationrule described in document 3GPP/TSG/RAN/WG1/TSGR1#6(99)997 “Textproposal for rate matching signaling”.

A prerequisite for this rule is to determine a transport formatcombination l⁰ for which the composite rate is maximum. For thistransport format combination l₀, the variations ΔN_(k) ^(MF) for blockswith N_(k) ^(MF) symbols before rate matching will be determined. Thisis done only for transport format combination l₀, in other words onlyfor all values kεMBS(l₀) . The upper index MF in the ΔN_(k) ^(MF) andN_(k) ^(MF) notations means that these parameters are calculated for amultiplexing frame and not for a TTI interval. By definition:$\begin{matrix}\left\{ {{\begin{matrix}{\forall{i \in \left\{ {1,\ldots \quad,T} \right\}}} \\{\forall{j \in {{TFS}(i)}}} \\{\forall{k \in {{CBS}\left( {i,j} \right)}}}\end{matrix}N_{k}^{MF}} = \left\lceil \frac{N_{k}}{F_{i}} \right\rceil} \right. & (3)\end{matrix}$

The next step is to proceed as if the rate matching 118 was carried outafter segmentation per multiplexing frame step 122 to define thevariations ΔN_(k) ^(MF). For flexible service positions, the variationsΔN_(k) ^(MF) for k∉MBS(l₀) are calculated using the following equation:$\begin{matrix}\left\{ {{\begin{matrix}{\forall{l \in \left\{ {1,\ldots \quad,C} \right\}}} \\{\forall{k \in {{{MSB}(l)}\quad {and}\quad k} \notin {{MSB}\left( l_{0} \right)}}}\end{matrix}\quad \Delta \quad N_{k}^{MF}} = \left\lfloor {\frac{\Delta \quad N_{\kappa {(k)}}^{MF}}{\quad N_{\kappa {(k)}}^{MF}} \cdot N_{k}^{MF}} \right\rfloor} \right. & (4)\end{matrix}$

where, for any coded block with index k, κ(k) is the element of MSB(l₀)such that coded blocks with index k and κ(k) originate from the samecoded transport channel and where └x┘ denotes the largest integer lessthan or equal to x.

For fixed service positions, the variations ΔN_(k) ^(MF) for k∉MSB(l₀)are calculated using the following equation: $\begin{matrix}\left\{ {{\begin{matrix}{\forall{l \in \left\{ {1,\ldots \quad,C} \right\}}} \\{\forall{k \in {{{MSB}(l)}\quad {and}\quad k} \notin {{MSB}\left( l_{0} \right)}}}\end{matrix}\quad \Delta \quad N_{k}^{MF}} = {\Delta \quad N_{\kappa {(k)}}^{MF}}} \right. & \left( {4\quad {bis}} \right)\end{matrix}$

Note that the definition of κ(k) does not create any problem with thismethod since, for any value of (i,j), CBS(i,j) comprises a singleelement and therefore if i is the index of the coded transport channelthat produces the coded block with indexed size k, then κ(k) is definedas being the single element of CBS(i,l₀).

With this rule, it is guaranteed that CBS(i,j) is a singleton since,firstly the number of coded blocks per TTI interval is not more than one(basic assumption), and secondly when this number is zero it isconsidered that the block size is zero and CBS(i,j) then contains asingle element k with N_(k)=0.

Finally, the set of variations ΔN_(k) is calculated using the followingequation: $\left\{ {{\begin{matrix}{\forall{i \in \left\{ {1,\ldots \quad,T} \right\}}} \\{\forall{j \in {{TFS}(i)}}} \\{\forall{k \in {{CBS}\left( {i,j} \right)}}}\end{matrix}\Delta \quad N_{k}} = {{F_{i} \cdot \Delta}\quad N_{k}^{MF}}} \right.$

which, in terms of variation, corresponds to the inverse operation ofequation (3), by reducing the considered multiplexing frame period to aTTI interval.

The following problems arise with this calculation rule:

1) nothing is written to say what is meant by the composite rate (theexact rate can only be determined when the variations ΔN have beencalculated; therefore, it cannot be used in the calculation rule);

2) even if this concept were defined, it is probable that there are somecases in which the transport format combination that gives the maximumcomposite rate is not unique; the result is that the definition of thecombination l₀ is incomplete;

3) equation (4) introduces a major problem. The transport formatcombination for which the composite rate is maximum is not necessarilysuch that all transport channels are simultaneously at their maximumrates. In the following, the number of symbols available permultiplexing frame for the CCTrCH composite will be called the maximumphysical rate N_(data). The maximum physical rate depends on theresources in allocated physical channels DPDCH. Therefore, it ispossible that the maximum physical rate N_(data) of the physicalchannel(s) carrying the composite is insufficient for all transportchannels to be at their maximum respective rates simultaneously.Therefore in this case, there is no transport format combination inwhich all transport channels are at their maximum rates simultaneously.Thus, transport channel rates are not independent of each other. Sometransport channels have a lower priority than others such that when themaximum physical rate N_(data) is insufficient, only the highestpriority transport channels are able to transmit, and transmission forthe others is delayed. Typically, this type of arbitration is carriedout in the medium access control (MAC) sub-level of the level 2 layer inthe OSI model. Since transport channels are not necessarily at theirmaximum rates simultaneously when the composite is at its maximum ratein transport format combination l₀, in particular it is possible thatone of them is at zero rate; therefore, it is possible to find a valuek₀εMBS(l₀) such that N_(k) ₀ ^(MF)=0, and consequently ΔN_(k) ₀ ^(MF)=0.If k₁εMBS(l₀) is such that k₀=κ(k₁), equation (4) then becomes asfollows for k=k₁:${\Delta \quad N_{k_{1}}^{MF}} = {\left\lfloor {\frac{\Delta \quad N_{k_{0}}^{MF}}{N_{k_{0}}^{MF}} \cdot N_{k_{1}}^{MF}} \right\rfloor = \left\lfloor {\frac{0}{0} \cdot N_{k_{1}}^{MF}} \right\rfloor}$

It then includes 0/0 type of indeterminate value. In the same way, it ispossible that N_(k) ₀ ^(MF) is very small compared with N_(k) ₁ ^(MF),even if it is not 0. Thus, whereas the composite is in the transportformat combination l₀ at its maximum rate, the transport channelcorresponding to coded block indexes k₀ and k₁ is at a very low rateN_(k) ₀ ^(MF) compared with another possible rate N_(k) ₁ ^(MF) for thesame transport channel. The result is that equation (4) giving ΔN_(k) ₁^(MF) as a function of ΔN_(k) ₀ ^(MF) amplifies the rounding error madeduring determination of ΔN_(k) ₀ ^(MF) by a factor$\frac{\quad N_{k_{1}}^{MF}}{N_{k_{0}}^{MF}}$

which is very large compared with one. However, such amplification ofthe rounding error in this way is not desirable.

One purpose of the invention is to suggest a rule for overcoming thedisadvantages described above.

Another purpose of the invention is to provide this type of method thatcan define rate matching for the downlink for all possible situations,and particularly for at least one of the following cases:

when ΔN_(k) ₀ ^(MF) and N_(k) ₀ ^(MF) are zero simultaneously;

the $\frac{\quad N_{k_{1}}^{MF}}{N_{k_{0}}^{MF}}$

ratio is very large compared with 1;

the rate of at least some transport channels of a transport channelcomposite depends on at least some other transport channels in the sametransport channel composite.

Another purpose of the invention is to provide a method for minimizingthe number of dummy symbols (DTX) to be inserted when the rate of thecoded transport channel composite is maximum.

BACKGROUND OF INVENTION

Consequently, the subject of the invention is a method for configuring atelecommunication system comprising at least one sending entity and atleast one receiving entity, said sending and receiving entitiesimplementing a step for transmission of data transported on at least onephysical channel, said at least one physical channel transmitting atransport channel composite under formation and having its own maximumphysical rate offered by said at least one physical channel, saidtransport channel composite comprising at least two transport channels,said data transmission step being preceded by a data processingprocedure for each of said transport channels, said data processingprocedure comprising at least one rate matching step, said rate matchingstep transforming a number of symbols before said rate matching stepinto a number of symbols after said rate matching step, said number ofsymbols after said rate matching step being obtained approximately bymultiplying said number of symbols before said rate matching step by arate matching ratio specific to each of said at least two transportchannels, said transport channel composite having a number of symbolsapproximately equal to the algebraic sum of the numbers of symbols inthe transport channels after the corresponding rate matching steps insaid processing procedures for a period common to said processingprocedures,

characterized in that it comprises the following successive steps:

a step for determining, from at least one of said entities,

for each of said processing procedures, a first parameter related to therate matching, said first parameter being proportional to said ratematching ratio, and

for all said processing procedures, a second parameter representing saidmaximum physical rate;

a transmission step for said first and second parameters determined fromat least one of said entities, called the first entity, to another ofsaid entities, called the second entity; and

a step in which at least said second entity determines the variationbetween the number of symbols after said rate matching step and thenumber of symbols before said rate matching step, for each of saidprocessing procedures, starting from one of said first and secondtransmitted parameters, such that the maximum rate of said transportchannel composite obtained does not cause an overshoot of said maximumphysical rate of said at least one physical channel.

Note that data blocks to which the rate matching step 118 is applicableare the coded blocks originating from the channel encoding step 108 (seeFIG. 1).

According to one important characteristic of the invention, said step inwhich the variation between the number of symbols after said ratematching step and the number of symbols before said rate matching stepis determined starting from one of said first and second transmittedparameters includes at least some of the following steps:

a step in which a temporary variation is calculated for each of saiddata block types starting from said first and second parameters and saidnumber of symbols before said rate matching step;

a correction step of said temporary variations for all said transportformat combinations, such that a temporary rate of the composite, saidtemporary rate resulting from said temporary variations, does not causean overshoot of said maximum physical rate for the all said transportformat combinations, said correction step being called the globalcorrection step;

a step in which final variations are determined.

Another subject of the invention is a configuration apparatus of thetype comprising at least means of transmitting data transported on atleast one physical channel, said at least one physical channeltransmitting a transport channel composite under formation and with amaximum physical rate offered by said at least one physical channel,said transport channel composite comprising at least two transportchannels, said apparatus comprising a data processing module comprisingat least rate matching means for each of said transport channels, saidrate matching means transforming a number of input symbols to said ratematching means into a number of output symbols from said rate matchingmeans obtained approximately by multiplying said number of input symbolsby a rate matching ratio specific to said at least one transport channelconcerned, said transport channel composite having a number of symbolsapproximately equal to the algebraic sum of the numbers of transportchannel symbols originating from the corresponding rate matching meansin said processing modules for a period common to said processing,

characterized in that it comprises:

means of determining a first parameter related to the rate matchingproportional to said rate matching ratio for each of said processingmodules, and a second parameter representative of said maximum physicalrate for the set of said processing modules, from at least one of saidentities;

means of transmitting said first and second determined parameters fromat least one of said entities called the first entity, to another ofsaid entities called the second entity; and

means by which at least said second entity determines the variationsbetween the number of output symbols from and the number of inputsymbols to said rate matching means starting from said first and secondtransmitted parameters, for each of said processing modules, such thatthe maximum rate obtained for said transport channel composite does notcause an overshoot of said maximum physical rate of said at least onephysical channel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram for downlink rate matching according to theprior art;

FIG. 2 is an example of variable channel rates according to the priorart;

FIG. 3 is a flow diagram for downlink rate matching according to thepresent invention;

FIG. 4 is a first alternative flow chart for downlink rate matchingaccording to the present invention;

FIG. 5 is a second alternative flow chart for downlink rate matchingaccording to the present invention;

FIG. 6 is a flow chart for downlink rate matching corrections accordingto the present invention.

The invention will be better understood after reading the followingdescription which is given solely as an example and which is given withreference to the attached drawings including FIGS. 3 to 5 whichrepresent the different methods of calculating the variations ΔN_(k)according to the invention, and FIG. 6 represents a step in which thetemporary variations are partially corrected.

DETAILED DESCRIPTION

The following description applies to the case of flexible servicepositions, unless specifically mentioned otherwise.

According to the invention, each coded transport channel i ischaracterized by two parameters RM_(i) and P_(i). The first parameterRM_(i) represents a rate matching attribute for coded transport channeli. This attribute is proportional to the Eb/I ratio expected inreception, in other words if several coded transport channels denoted 1,2, . . . , T, are considered with attributes denoted RM₁, RM₂, . . . ,RM_(T) respectively, then the expected Eb/I ratios for each codedtransport channel will be in the same proportions as the RM_(i)parameters. The second parameter P_(i) is a coefficient corresponding tothe maximum allowable puncturing ratio for a given coded transportchannel i. Thus, a maximum puncturing ratio denoted P₁, P₂, . . . ,P_(T) is associated with each coded transport channel 1, 2, . . . , T.The maximum puncturing ratio is imposed by the channel coding used inthe processing system specific to the coded transport channelconsidered. Puncturing consists of eliminating coded symbols. Thiselimination is tolerable since channel encoding introduces a redundancy.However, the number of punctured symbols cannot be too large comparedwith the total number of coded symbols, therefore there is a maximumpuncturing ratio that depends on the channel coding and the decoder usedin reception.

Furthermore, note that the maximum physical rate N_(data) is the maximumnumber of symbols that can be transmitted in a multiplexing frame,allowing for the allocation of one or several physical channels DPDCH.

According to the invention, only the set of parameters {RM₁} whereiε[1,T], and N_(data) are transmitted on a logical control channelassociated with a previously existing coded transport channel composite,in order to enable each telecommunication system entity to know the setof correspondences between the numbers of symbols after rate matchingN+ΔN and the numbers of symbols before rate matching N, for each codedtransport channel. A logical channel denotes a channel that can connecttwo level 3 layer protocols, typically two Radio Resource Control (RRC)protocols. This type of logical channel is carried by one of thetransport channels within a previously existing coded transport channelcomposite.

These parameters {RM_(i)}_(iε[1,T]) and N_(data) may be determined byone of the entities, or they may be “negotiated” between severalentities. Note that N_(data) is a positive non-null integer and the{RM_(i)}_(iε[1,T]) parameters are also positive and non-null, and mayalso typically be expressed simply as binary numbers.

At the end of the negotiation, the {RM_(i)}_(iε[1,T]) and N_(data)parameters come into force at a moment determined by the negotiation todefine the (N, ΔN) pairs for each coded transport channel and for eachof their respective transport formats within a new transport channelcomposite. Note that this new composite is the result of the compositeunder formation before the instant at which the RM_(i) and N_(data)parameters came into force. This new composite typically replaces thepreviously existing composite on which the negotiation took place. It isimpossible to make any negotiation when there is no previously existingtransport channel composite on the dedicated physical channels DPDCH induplex at the time that a transport channel composite is set up. Underthese conditions, the number of coded transport channels T and the{RM_(i)}_(iε[1,T]) and N_(data) parameters of the new coded transportchannel composite are either predefined for the system, or aredetermined in a simplified negotiation for which dedicated physical datachannels do not have to exist in advance. Typically, this type ofnegotiation may take place on common physical channels such as thePhysical Random Access CHannel (PRACH) for the uplink, and the ForwardAccess Channel (FACH) for the downlink. This simplified negotiationcould also relate to a context including the {RM_(i)}_(iε[1,T]) andN_(data) information, this context having been set up during a previousconnection of dedicated physical data channels.

The RM_(i) parameters are such that the rate matching ratios RF_(i)associated with the same coded transport channel are proportional to theparameters, factored by a semi-static factor L independent of the codedtransport channel i. Therefore, we have:

∀iRF _(i) =L.RM _(i)  (5)

Furthermore, the following must be satisfied in order to respect theconstraint on the maximum puncturing ratio:

∀iRF _(i)≧1−P _(i)  (6)

Note that according to the invention, there is no need to know the valueof each parameter P_(i) to calculate the set of correspondences (N, ΔN).The system of equations (5) and (6) is equivalent to the system ofequations (5), (7) and (8) with respect to the factor L:

L≧L MIN  (7)

where $\begin{matrix}{{L\quad {MIN}} = {\max\limits_{i}\frac{1 - P_{i}}{R\quad M_{i}}}} & (8)\end{matrix}$

Therefore, all that has to be known is LMIN or any other proportionalvalue determined using a factor dependent on known data, for example${{PL} = {L\quad {{MIN} \cdot {\min\limits_{i}\quad {RM}_{i}}}}},$

to have the same information on all possible values of the rate matchingratios {RF_(i)}. However, this is not necessary. In fact, the factor Lis maximized as a function of N_(data) such that the number of insertedDTX symbols is minimum when the transport channel composite rate ismaximum. Consequently, since N_(data) is sufficiently large so thatequation (7) is satisfied when the L factor is at a maximum, there is noneed to know the P_(i) parameters or any other parameter (for exampleLMIN) giving a puncturing limit to determine the variations ΔN. All thatis necessary is that the method used to calculate the correspondences(N, ΔN) maximizes the L factor, in other words minimizes the number ofinserted DTX symbols for the maximum rate of the transport channelcomposite. However, this does not mean that the values of the P_(i), PLor LMIN parameters are not negotiated. It simply means that all that isnecessary to calculate correspondences (N, ΔN) according to theinvention is to know the value of the maximum physical rate N_(data) inaddition to the value of the parameters {RM_(i)}.

Thus, if l is the index of a transport formats combination, and if thecoded transport channel i is in transport format index j in thistransport formats combination (in other words j=TF_(i)(l)), then foreach coded block with index k in coded transport channel i with format j(in other words kεCBS(i,j)), if N_(k)+ΔN_(k) is the number of symbolsbefore segmentation step 122, the segments will have not more than$\left\lceil \frac{N_{k} + {\Delta \quad N_{k}}}{F_{i}} \right\rceil$

symbols at the end of this step. The result is that when considering allk type coded blocks, where kεCBS(i,TF_(i)(l)) on the coded transportchannel i for the transport formats combination with index 1 and allcoded transport channels iε{1, . . . , T}, it is deduced that the totalnumber of symbols D(l) in a multiplexing frame of the transport formatcombination, l is equal to not more than the following sum:$\begin{matrix}{{D(l)} = {\sum\limits_{i = 1}^{i = T}{\sum\limits_{k \in {{CBS}{({i,{{TF}_{i}{(l)}}})}}}\left\lceil \frac{N_{k} + {\Delta \quad N_{k}}}{F_{i}} \right\rceil}}} & (9)\end{matrix}$

Furthermore, given the rate limits of the dedicated physical datachannels, we have:

∀lε{1, . . . , C}D(l)≦N _(data)  (10)

Note that N_(data)-D(l) is the number of DTX symbols inserted duringstep 132 for the transport formats combination 1.

Since it is required to minimize the number of DTX symbols insertedduring step 132 when the transport channel composite rate is maximum, weneed:

max D(l)≈N _(data)1≦l≦C  (11)

Also, according to the invention, the calculation of the variationΔN_(k) for any value of k includes mainly three phases. In the firstphase, temporary variations denoted ΔN_(k) ^(temp) are calculated so asto satisfy equation (11). In the second phase, these temporaryvariations are corrected by a “global” correction step in order tosatisfy the relation (10), and in the third phase the final variationsare generated by assigning the most recent temporary variations obtainedto them. These three phases are illustrated in FIGS. 3, 4 and 5 whichshow three different methods of calculating the variations ΔN_(k).Identical steps are referenced by the same number in each of thesefigures.

Phase 1: Calculation of Temporary Variations

Note that N_(k)+ΔN_(k)≈RF_(i).N_(k) is true for all values ofkεCBS(i,j). According to equation (5), we can then write:$\begin{matrix}{{D(l)} \approx {L \cdot {\sum\limits_{i = 1}^{i = T}{\sum\limits_{k \in {{CBS}{({i,{{TF}_{i}{(l)}}})}}}\quad \frac{R\quad {M_{i} \cdot N_{k}}}{F_{i}}}}}} & (12)\end{matrix}$

The member at the right of this equation is a rate estimator of thecomposite CCTrCH for the transport formats combination 1. This equation(12) can then be used to find an approximate value of the factor Lmaximized under the constraint represented by equation (10) to satisfyequation (11). According to a first embodiment illustrated in FIG. 3,this value is given by the following equation: $\begin{matrix}{L = \frac{N_{data}}{\max\limits_{1 \leq l \leq C}{\sum\limits_{i = 1}^{i = T}{\sum\limits_{k \in {{CBS}{({i,{{TF}_{i}{(l)}}})}}}\quad \frac{R\quad {M_{i} \cdot N_{k}}}{F_{i}}}}}} & (13)\end{matrix}$

Note that the denominator in the member at the right of equation (13) isthe maximum value of the rate estimator of the composite CCTrCH for thetransport format combinations and calculated assuming L=1 (which isequivalent to assume fictitiously that RF₁=RM_(i)).

This calculation step is denoted 301 in FIG. 3. Note that transmissionof the N_(data) parameter is referenced 300A in FIG. 3. Similarly, thetransmission of parameters {RM_(i)}_(1≦i≦T) and the transmission of thenumbers of symbols {N_(k)}_(kεCBS(i,TF) ₁ _((l))) are denoted 300B and300C respectively.

We then determine the values of the various rate matching ratios RF_(i),making use of equations (5) and (13), in a step 302.

The temporary variation ΔN_(k) ^(temp) for each type k is thendetermined in a step 303, for example using the following equation:$\begin{matrix}\left\{ {{\begin{matrix}{\forall{i \in \left\{ {1,\ldots \quad,T} \right\}}} \\{\forall{j \in {{TFS}(i)}}} \\{\forall{k \in {{CBS}\left( {i,j} \right)}}}\end{matrix}\Delta \quad N_{k}^{temp}} = {\left\lceil {{RF}_{i} \cdot N_{k}} \right\rceil - N_{k}}} \right. & (14)\end{matrix}$

As a variant, equation (14) could be replaced by equation (14bis) givenbelow. This equation has the advantage that the number of symbols afterrate matching N_(k)+ΔN_(k) provided (assuming ΔN_(k)=ΔN_(k) ^(temp)) atthe beginning of the segmentation step 122 (FIG. 1) is a multiple of thenumber F_(i) of segments to be produced. Thus, all segments originatingfrom the same block have the same number of symbols, which simplifiesthe receiver since the number of symbols does not vary during the TTIinterval. $\begin{matrix}\left\{ {{\begin{matrix}{\forall{i \in \left\{ {1,\ldots \quad,U} \right\}}} \\{\forall{j \in {{TFS}(i)}}} \\{\forall{k \in {{CBS}\left( {i,j} \right)}}}\end{matrix}\Delta \quad N_{k}^{temp}} = {{F_{i}\left\lceil \frac{{RF}_{i} \cdot N_{k}}{F_{i}} \right\rceil} - N_{k}}} \right. & \left( {14\quad {bis}} \right)\end{matrix}$

As a variant, it would be possible to use a rounding function other thanthe x┌x┐ function in equation (14) or (14bis). For example, it would bepossible to use the x└x┘ function, where └x┘ is the largest integer lessthan or equal to x.

It would also be possible to consider calculating the factor L and therate matching ratio RF_(i) by making approximations, for example byexpressing L and/or RF_(i) as a fixed decimal number with a limitednumber of digits after the decimal point. This embodiment is illustratedin FIG. 4.

Thus as a variant, the factor L is calculated using the followingequation, in a step 401: $\begin{matrix}{L = {\frac{1}{LBASE} \cdot \left\lfloor \frac{{LBASE} \cdot N_{data}}{\max\limits_{1 \leq l \leq C}{\sum\limits_{i = 1}^{i = T}{\sum\limits_{k \in {{CBS}{({i,{{TF}_{i}{(l)}}})}}}\frac{{RM}_{i} \cdot N_{k}}{F_{i}}}}} \right\rfloor}} & \text{(13bis)}\end{matrix}$

where LBASE is an integer constant, for example a power of 2 such as2^(n), where n is the number of bits in the L factor after the decimalpoint.

The rate matching ratios RF_(i) are then calculated in a next step 402using the following equation: $\begin{matrix}{{\forall{i\quad {RF}_{i}}} = {\frac{1}{RFBASE} \cdot \left\lfloor {{RFBASE} \cdot L \cdot {RM}_{i}} \right\rfloor}} & \text{(5bis)}\end{matrix}$

where RFBASE is an integer constant, for example a power of 2 such as2^(n), where n is the number of bits after the decimal point in RF_(i).

In the same way as for equations (5) and (14), the x└x┘ function inequations (5bis) and (14bis) can be replaced by any other roundingfunction.

According to a third embodiment illustrated in FIG. 5, the expression ofthe factor L is modified by using a coefficient that depends on knowndata (for example {RM_(i)} or N_(data)), in the numerator and in thedenominator. This could have an impact on the calculated values to theextent that the expression of the factor L uses an approximation. Forexample, the following equation could be used: $\begin{matrix}{L = {\frac{1}{{LBASE} \cdot \left( {\min\limits_{1 \leq i \leq T}{RM}_{i}} \right)} \cdot \left\lfloor \frac{{LBASE} \cdot \left( {\min\limits_{1 \leq i \leq T}{RM}_{i}} \right) \cdot N_{data}}{\max\limits_{1 \leq l \leq C}{\sum\limits_{i = 1}^{T}{\sum\limits_{k \in {{CBS}{({i,{{TF}_{i}{(l)}}})}}}\frac{{RM}_{i} \cdot N_{k}}{F_{i}}}}} \right\rfloor}} & \text{(13ter)}\end{matrix}$

The rate matching ratios RF_(i) are then calculated using equation (5)or (5bis).

In summary, the phase in which the temporary variations ΔN_(k) ^(temp)are calculated comprises the following steps:

1. Calculate the factor L as a function of the maximum physical rateN_(data) and the RM_(i) parameters (step 301, 401 or 501).

2. Calculate the rate matching ratio RF_(i) for each coded transportchannel i, as a function of the RM_(i) parameters and the factor L (step302, 402 or 502).

3. For each k type coded block in a coded transport channel i, calculatethe temporary variation ΔN_(k) ^(temp) as a function of the number ofsymbols N_(k) before rate matching and the rate matching ratio RF_(i)(step 303).

Phase 2: Global Correction of Temporary Variations

In this second phase, an iterative check is carried out to verify thatthe number of symbols D^(temp)(l) per multiplexing frame for the CCTrCHcomposite is less than or equal to the maximum physical rate N_(data),for each transport format combination with index l, where D^(temp)(l) isdetermined using current values of temporary variations ΔN_(k) ^(temp),in other words initially with variations determined during the firstphase and then with the most recent temporary variations calculatedduring the second phase. If necessary, the value of the temporaryvariations ΔN_(k) ^(temp) is corrected. This step is also called theglobal temporary variations correction step for all transport formatcombinations l. This step is marked as reference 308 in FIGS. 3, 4 and5.

If equation (9) is rewritten with temporary variations ΔN_(k) ^(temp),the following expression of the temporary rate D^(temp)(l) of thecomposite is obtained: $\begin{matrix}{{D^{temp}(l)} = {\sum\limits_{i = 1}^{T}{\sum\limits_{k \in {{CBS}{({i,{{TF}_{i}{(l)}}})}}}\left\lceil \frac{N_{k} + {\Delta \quad N_{k}^{temp}}}{F_{i}} \right\rceil}}} & \text{(9bis)}\end{matrix}$

This calculation is carried out in step 304 in FIGS. 3, 4 and 5. Asdescribed previously, this second phase implies thatD^(temp)(l)≦N_(data), for each transport format combination with indexl.

Every time that a transport format combination l is detected such thatD^(temp)(l)>N_(data), then the values of some temporary variationsΔN_(k) ^(temp) are corrected by a “partial correction” step. Thus, thevalues of some temporary variations ΔN_(k) ^(temp) are reduced in thisstep so that the temporary rate D^(temp)(l) of the composite is lessthan the maximum physical rate N_(data) after correction.

Considering that the temporary rate D^(temp)(l) of the composite is anincreasing function that depends on temporary variations ΔN_(k) ^(temp),a partial correction applied to the transport format combination withindex l does not change the result of verifications already made forprevious transport format combinations. Therefore, there is no point ofrechecking that D^(temp)(l)≦N_(data) for previously verifiedcombinations.

The second phase is summarized by the following algorithm:

for all values of l from 1 to C, do

if D^(temp)(l)≦N_(data) then

partial correction of ΔN_(k) ^(temp) values

end if

end do.

The step in which the maximum physical rate N_(data) is compared withthe temporary rate D^(temp)(l) of the composite and the step in whichtemporary variations ΔN_(k) ^(temp) are partially corrected, are denoted305 and 306 respectively in FIGS. 3, 4 and 5. The final variationsΔN_(k) are the temporary variations ΔN_(k) ^(temp) obtained at the endof the second phase. This assignment step forms the third phase.

We will now describe the partial correction step of the temporaryvariations ΔN_(k) ^(temp) mentioned in line 3 of the previous algorithm.In the remainder of the description of the partial correction, allnotation used is applicable for a current index l of the transportformat combination. l is not always given in the new expressions, inorder to simplify the notation.

Remember that MBS(l) is the set of coded block indexes for the transportformat combination l. In other words, we have:${{MSB}(l)} = {\bigcup\limits_{1 \leq i \leq T}{{CBS}\left( {i,{{TF}_{i}(l)}} \right)}}$

Let U be the number of elements of MBS(l). Since MBS(l) is a set ofinteger numbers, it is ordered into the canonical order of integernumbers. Therefore, it is possible to define a strictly increasingmonotonic bijection K from {1, . . . , U} to MBS(l). We then have:

MBS(l)={K(1),K(2), . . . , K(U)}

where

K(1)<K(2)<. . . <K(U)

Note that any other ordering rule can be used as a variant, for exampleanother bijection of {1, . . . , U} to MBS(l). (K(1), . . . , K(U))defines an ordered list. Similarly, for every coded block with index kin MBS(l), there is a single coded transport channel i producing thiscoded block for the transport format combination with index l such thatkεCBS(i,TF_(i)(l)). Therefore, it is possible to univocally define anapplication I from {1, . . . , U} to {1, . . . , T}, which identifiesthe single transport channel with index i=I(x) such thatkεCBS(i,TF_(i)(l)) for each coded block with index k=K(x).

Thus, a partial sum S_(m) can be defined for all values of mε{1, . . . ,U}, for m equal to U, a total sum S_(U), and an coefficient Z_(m)increasing as a function of m such that: $\begin{matrix}{S_{m} = {\sum\limits_{x = 1}^{x = m}{{RM}_{I{(x)}} \cdot \frac{N_{K{(x)}}}{F_{I{(x)}}}}}} & (16) \\{Z_{m} = \left\lfloor {\frac{S_{m}}{S_{U}} \cdot N_{data}} \right\rfloor} & (17)\end{matrix}$

Note that, like for any coded transport channel i, 8 is a multiple ofthe duration F_(i) expressed as a number of multiplexing frames in theTTI interval in the coded transport channel i, then the partial sumS_(m) can be coded without approximation as a fixed decimal number with3 bits after the decimal point.

As a variant, the x└x┘ rounding function in equation (17) may bereplaced by any other increasing monotonic rounding function.

Assuming Z₀=0, new variations called the intermediate variations ΔN_(k)^(new) can then be defined and can replace the temporary variationsΔN_(k) ^(temp) used for the transport format combination l. Theseintermediate variations ΔN_(K(x)) ^(new) are given by the followingequation:

∀xε{1, . . . , U}ΔN _(K(x)) ^(new)=(Z _(x) −Z _(x−1)).F _(l(x)) −N_(K(x))  (18)

In summary, temporary variations ΔN_(k) ^(temp) are partially correctedusing the following algorithm:

for all x from 1 to U, do

if ΔN_(K(x)) ^(temp)>ΔN_(K(x)) ^(new) then

ΔN_(K(x)) ^(temp)←ΔN_(K(x)) ^(new)

end if

end do.

Note that the ← symbol in the third line of the algorithm means that thevalue of ΔN_(K(x)) ^(temp) is changed, and that it is replaced by thevalue of ΔN_(K(x)) ^(new).

This partial correction step is illustrated in FIG. 6. In a first step601, the intermediate variation ΔN_(K(x)) ^(new) is calculated and isthen compared with the value of the corresponding temporary variationΔN_(K(x)) ^(temp) in a step 602. If ΔN_(K(x)) ^(temp)>ΔN_(K(x)) ^(new),the value of the intermediate variation ΔN_(K(x)) ^(temp) is assigned tothe temporary variation ΔN_(K(x)) ^(temp) in a step 603, and then thenext step 604 is executed. If ΔN_(K(x)) ^(temp)<ΔN_(K(x)) ^(new), thenext step 604 is executed directly. In this step 604, it is checkedwhether x is equal to the value U. If it is not, x is incremented in astep 605, and then step 601 is carried out again with this new value ofx. If x is equal to U, the partial correction step is terminated.

Phase 3: Determination of Final Variations

Remember that during this third phase, the value of the final variationsΔN_(k) are the values of the temporary variations ΔN_(k) ^(temp)originating from the second phase. This phase corresponds to step 307 inFIGS. 3, 4 and 5. Consequently, the value of the final rate D(l) of thecomposite is equal to the value given by equation (9), for a giventransport formats combination l.

In order to enable blind rate detection, a “fixed service positions”technique comprises the step in which DTX symbols are inserted in step116 such that the rate (including DTX symbols) at the end of this step116 is constant.

Consequently, all steps following encoding of the channel are carriedout independently of the current rate. Thus in reception,demultiplexing, de-interleaving steps, etc., can be carried out inadvance without knowing the current rate. The current rate is thendetected by the channel decoder (performing the reverse of the operationdone by the channel encoder 108).

In order for the step inverse to step 118 of rate matching to beindependent of the current rate, the puncturing pattern or repetitionpattern should be independent of the rate, in other words the number ofcoded blocks and the numbers of symbols N in each.

Thus firstly, in the case of fixed service positions there is never morethan one coded block per TTI interval, and in fact it is considered thatthere is always one if it is assumed that the lack of a coded block isequivalent to the presence of a coded block without a symbol.Consequently, the number of blocks does not vary as a function of therate.

The optimum puncturing/repetition pattern depends on the N and ΔNparameters giving the number of symbols before rate matching and thevariation due to rate matching, respectively. Therefore, these twoparameters need to be constant to obtain a pattern independent of therate, in other words the rate matching step 118 should be placed afterstep 122 in which DTX symbols are inserted. However, since all DTXsymbols are identical, puncturing them or repeating them atpredetermined positions induces unnecessary complexity (the same resultcan be achieved by puncturing or repeating the last DTX symbols in theblock, and this is easier to implement). Therefore, it was decided thatthe rate matching step 118 and the DTX symbol insertion step 122 wouldbe carried out in this order as shown in FIG. 1, but that therepetition/puncturing pattern would be determined only for the case inwhich the composite is at its maximum rate. The pattern thus obtained istruncated for lower rates.

Note that in prior art, the fixed service positions and flexible servicepositions are two mutually exclusive techniques. In the invention, it ispossible to have some transport channels in fixed service positions, andother channels in flexible service positions. This makes it possible tocarry out blind rate detection only for transport channels in fixedservice positions, and a rate detection using an explicit rateinformation for the other transport channels. Thus, the explicit rateinformation, TFCI, only indicates current transport formats fortransport channels in flexible service positions. The result is that alower capacity is necessary for TCFI transmission.

In the case of combined fixed and flexible service positions, somecomposite transport channels are in fixed service positions and othersare in flexible service positions. step 116 in which DTX symbols areinserted is only present for coded transport channels in fixed servicepositions, and it is missing for other transport channels that are inflexible service positions. Furthermore, the DTX symbol insertion step132 is present if there is at least one coded transport channel in fixedservice positions, and otherwise it is missing.

During reception of a multiplexing frame and the associated TFCI, thereceiver may implement all steps inverse to those following the channelencoding. The TFCI information gives it the encoding format of codedtransport channels in flexible service positions, and for transportchannels in fixed service positions, the receiver acts as if they werein the highest rate transport format.

In the invention, the repetition/puncturing pattern depends on the twoparameters N and ΔN, regardless of whether the coded transport channelis in the fixed service positions or flexible service positions, howeverin the flexible service position N and ΔN correspond to the number ofsymbols before rate matching and to the variation of this number duringthe rate matching step 118 respectively, while in fixed servicepositions they are only two “fictitious” parameters used to determinethe puncturing pattern when the coded transport channel rate is notmaximum. In other words, these two parameters correspond to the size ofthe block for which the rate is to be matched, and its variation afterrate matching when the rate of the coded transport channel is maximum.

When the rate of the coded transport channel is not maximum, thepuncturing/repetition pattern is truncated. This pattern is actually alist of symbol positions that are to be punctured/repeated. Truncatingconsists of considering only the first elements in this list, which arereal positions in the block for which the rate is to be matched.

Thus according to the invention, when there is at least one codedchannel in the fixed service positions, rate matching parameters aredetermined in the same way as when all coded transport channels are inthe flexible service positions, except that coded transport channels infixed service positions are considered fictitiously to be at theirmaximum rate.

Consider the example in FIG. 2, and assume that coded transport channelD is in the fixed service 10 position, whereas transport channels A, Band C are in flexible service positions. The table below shows the listof transport format combinations for this example.

Transport format for Combination transport channels example frame withindex A B C D this combination  0 0 2 0 0 11   1 0 2 0 2 10   2 0 3 0 012   3 0 3 0 1 13   4 0 2 2 1 8  5 2 0 2 1 0  6 0 2 2 2 9  7 2 1 1 0 5 8 2 0 2 2 1 and 2  9 0 3 2 1 14 and 15 10 2 1 1 1 4 11 2 0 2 3 3 12 2 12 1 6 and 7

The rate matching configuration parameters are calculated in the sameway as for flexible service positions, except that it includes theadditional prior step of fictitiously replacing the column in this tablecorresponding to coded transport channel D, by setting all elements tothe transport format for the highest rate, in other words the transportformat with index 3. This gives the following “fictitious” table inwhich the boxes that have been modified and which correspond to“fictitious” transport formats are shown in grey:

Transport format for Combination transport channels Example frame withindex A B C D this combination  0 0 2 0 3 11   1 0 2 0 3 10   2 0 3 0 312   3 0 3 0 3 13   4 0 2 2 3 8  5 2 0 2 3 0  6 0 2 2 3 9  7 2 1 1 3 5 8 2 0 2 3 1 and 2  9 0 3 2 3 14 and 15 10 2 1 1 3 4 11 2 0 2 3 3 12 2 12 3 6 and 7

By definition, coded transport channels i in the fixed servicespositions, have not more than one coded block per TTI interval(∀jεTFS(i) CBS(i,j) has not more than one element).

Furthermore, in the invention it is assumed that coded block sizes areindexed such that the absence of a coded block for coded transportchannels in fixed service positions leads to indexing with theconvention that the absence of a block is equivalent to the presence ofa zero size block (i.e. an index k is assigned with N_(k)=0, andtherefore ∀jεTFS(i) CBS(i,j) has at least one element).

With the previous assumptions, the first phase in the calculation of thetemporary variations ΔN_(k) ^(temp), which has already been described,must be preceded by the following step when there is at least one codedtransport channel in the fixed service positions.

For all i from 1 to T do

if the coded transport channel with index i is in the fixed servicepositions then

for all values of j in TFS(i), do

let k be the single element of CBS(I,j)$\left. N_{k}\leftarrow{\max\limits_{\underset{k^{\prime} \in {{CBS}{({i,j^{\prime}})}}}{j^{\prime} \in {{TFS}{(i)}}}}N_{k^{\prime}}} \right.$

end do

end if

end do

The fifth instruction means that the coded transport channel I isfictitiously considered to be at its maximum rate; its actual rate(N_(k)) is replaced (←) by its maximum rate$\left( {\max\limits_{\underset{k^{\prime} \in {{CBS}{({i,j^{\prime}})}}}{j^{\prime} \in {{TFS}{(i)}}}}N_{k^{\prime}}} \right).$

What is claimed is:
 1. A method for configuring a telecommunicationsystem comprising a plurality of entities, said entities implementing astep for transmission of data transported on at least one physicalchannel, said at least one physical channel transmitting a transportchannel composite and having a maximum physical rate, said transportchannel composite comprising a plurality of transport channels, saiddata transmission step being preceded by a data processing procedure foreach of said transport channels, said data processing procedurecomprising at least one rate matching step, said rate matching steptransforming a number of symbols before said rate matching step into anumber of symbols after said rate matching step, said number of symbolsafter said rate matching step being obtained approximately bymultiplying said number of symbols before said rate matching step by arate matching ratio specific to each of said transport channels, whereinsaid method comprises a determining step in which at least one of saidentities as a first entity determines a variation between the number ofsymbols after said rate matching step and the number of symbols beforesaid rate matching step, for each of said processing procedures, basedon a first parameter and a second parameter, said first parameterrepresenting said rate matching ratio for each of said processingprocedures, said second parameter representing said maximum physicalrate for said transport channel composite, at least one transport formatis defined for each transport channel, at least one transport formatcombination determines a transport format among said defined transportformats for each of said transport channels, each transport channelcomprising at least one data block type, said data block type dependingat least on said transport channel and a transport format of thetransport channel concerned, each data block type defining a number ofsymbols of the concerned data block before said rate matching step, andsaid step of determining the variation between the number of symbolsbefore said rate matching step and the number of symbols after said ratematching step comprises: calculating a temporary variation for each ofsaid at least one data block type starting from said first and secondparameters and said number of symbols before said rate matching step;correcting a temporary rate for said transport channel compositeresulting from said calculated temporary variation for each of said atleast one data block type, for said at least one transport formatcombination, so that said temporary rate does not exceed said maximumphysical rate for said at least one transport format combination, saidcorrection step being a global correction step; and determining finalvariations for said at least one transport format combination, a finalvariation being determined for each of said at least one data blocktype.
 2. The method according to claim 1, wherein said calculation stepcomprises the following for each of said transport channels: a firststep to calculate the rate matching ratio of the transport channelconcerned as a function of said first and second parameters and saidnumber of symbols before said rate matching step; a second step tocalculate temporary variations for each of said types of data blocksdepending on said transport channel concerned, said second calculationstep depending on said rate matching ratio and said number of symbolsbefore said rate matching step, so that said rate matching ratio isapproximately equal to the ratio between firstly the number of symbolsafter said rate matching step and secondly the number of symbols beforesaid rate matching step.
 3. The method according to claim 1, whereinsaid global correction step comprises the following steps iterativelyfor each of said at least one transport format combination: calculatinga temporary rate for said transport channel composite as a function ofsaid calculated temporary variation for each of said at least one datablock type and said number of symbols before said rate matching step,for the transport format combination concerned; comparing saidcalculated temporary rate for said transport channel composite with saidmaximum physical rate for the transport format combination concerned;and if said calculated temporary rate for said transport channelcomposite exceeds said maximum physical rate, correcting at least someof said calculated temporary variation for each of said at least onedata block type as a partial correction step.
 4. The method according toclaim 3, wherein said step calculating a temporary rate of the transportchannel composite is given by the following formula:${D^{temp}(l)} = {\sum\limits_{i = 1}^{i = T}{\sum\limits_{k \in {{CBS}{({i,{{TF}_{i}{(l)}}})}}}{\frac{N_{k} + {\Delta \quad N_{k}^{temp}}}{F_{i}}}}}$

where D^(temp)(l) is the temporary composite rate for transport formatcombination l; CBS(i,j) is the set of types of data blocks for transportchannel i for transport format j; TF_(i)(l) is the transport format fortransport channel i in the transport format combination l; T is thenumber of transport channels in the composite; N_(k) is the number ofsymbols in the data block type k; ΔN_(k) ^(temp) is the temporaryvariation in data block type k; and F_(i) is a factor specific totransport channel i.
 5. The method according to claim 3, wherein saidpartial correction step comprises: a step in which an ordered list of aset of data block types is created, said set being defined so that, foreach transport channel, an element of said set is a function of thetransport channel and the transport format determined for said transportchannel by the transport format combination concerned; for each elementin said list, a step in which a coefficient is calculated that increasesas a function of the order of said list; for each element of said list,a step in which an intermediate variation is calculated as a function ofthe difference between firstly said increasing coefficient and secondlyits predecessor if there is one, or otherwise is equal to a null value;for each element in said list, a step in which a corrected temporaryvariation is determined.
 6. The method according to claim 5, whereinsaid increasing coefficient is approximately equal to a product of themaximum physical rate by a factor representing the ratio between apartial sum and a total sum, the summation being made in an order ofsaid list.
 7. The method according to claim 6, wherein a generic term ofsaid partial and total sums is proportional to: said first parameter ofthe transport channel concerned corresponding to an element of said listfor which the summation is made; said number of symbols defined by thetype of data blocks corresponding to the element of said list for whichthe summation is made.
 8. The method according to claim 7, eachtransport channel being transmitted on at least one transmission timeinterval with a duration specific to the transport channel concerned,wherein said common period corresponding to the duration of amultiplexing frame, said step in which intermediate variations arecalculated is given by the following formula: ∀xε{1, . . . , U}ΔN_(K(x)) ^(new)=(Z _(x) −Z _(x−1))·F _(I(x))) −N _(K(x)) where ΔN_(K(x))^(new) is an intermediate difference, N_(K(x)) is the number of symbolsdefined by the type K(x) of data blocks; Z_(x) is the increasingcoefficient; and F_(I(x)) is the duration of said transmission timeinterval as a number of multiplexing frames.
 9. The method according toclaim 5, wherein said step to determine the corrected temporaryvariation is carried out assuming that the calculated intermediatevariation is less than the temporary variation corresponding to theelement in said list concerned, and in that said determination stepcomprises assigning the calculated intermediate variation to thetemporary variation.
 10. The method according to claim 1, wherein saidstep in which the final variations are determined comprises assigningthe last temporary variations to said final variations.
 11. The methodaccording to claim 2, wherein during said step to calculate the ratematching ratio, said calculated rate matching ratio is approximatelyequal to a product of firstly said first parameter for the transportchannel concerned and secondly a factor representing a ratio betweensaid maximum physical rate and an estimator of the maximum compositerate, said estimator being calculated assuming that each of said ratematching ratios is respectively equal to said first parameter as afunction of the transport channel concerned.
 12. A method forconfiguring a telecommunication system including a plurality of entitiesconfigured to transmit data on at least one physical channel, said atleast one physical channel transmitting a transport channel compositeand having a maximum physical rate, said transport channel compositecomprising a plurality of transport channels, each transport channelhaving at least one transport format, each transport formatcorresponding to a data block type, said at least one transport formatbeing predetermined for each transport channel, each of said transportchannels being processed by a separate and distinct processingprocedure, said transport channel composite having at least onetransport format combination, each transport format combinationresulting from a predetermined transport format for each of saidtransport channels, said method comprising the steps of: transforming,for a data block of each of said transport channels, an input number ofsymbols into an output number of symbols, said output number of symbolsbeing obtained approximately by multiplying said input number of symbolsby a rate matching ratio specific to each of said transport channels;and determining, for said data block of each of said transport channels,a variation between the output number of symbols and the input number ofsymbols based on a first parameter representing said rate matching ratiofor each processing procedure and a second parameter representing saidmaximum physical rate for said transport channel composite, saiddetermining step including, calculating a temporary variation, for eachof said at least one data block type, starting from said firstparameter, said second parameter, and said input number of symbols,correcting a temporary rate for said transport channel compositeresulting from said calculated temporary variation for each of said atleast one data block type, for each of said at least one transportformat combination, so that said temporary rate for said transportchannel composite does not exceed said maximum physical rate for said atleast one transport format combination, said correcting step being aglobal step, and determining a final variation for each of said at leastone data block type of each of said transport channels comprised withinsaid transport channel composite for said at least one transport formatcombination.